Inspecting apparatus and inspecting method for circuit board

ABSTRACT

The present invention provides an apparatus and method for inspecting a circuit board at a high speed. An LCD driver module  100  as an object to be inspected has an onboard LCD driving LSI  110.  One circuit-wiring group  111  is connected to SEG terminals, and another circuit-wiring group  112  is connected to COM terminals of the LSI  110.  An inspection apparatus  1  generates an LSI drive signal and sends it to input terminals  113  of the LSI  110.  A pair of sensors  2, 3  are positioned opposedly to the circuit-wiring groups  111, 112,  respectively, in a non-contact manner. Each of the sensors  2, 3  detects voltage changes in the corresponding circuit-wiring group  111, 112  caused by driving the LSI  110,  and the detected signals are analyzed by the inspection apparatus  1.

TECHNICAL FIELD

[0001] The present invention relates to an apparatus and a method forinspecting a circuit board.

BACKGROUND ART

[0002] In manufacturing processes of a circuit board, after formingcircuit wirings on a board, it is required to inspect the presence of adisconnection or open circuit in the circuit wirings.

[0003] Heretofore, an open circuit state in circuit wirings on a circuitboard has been determined by bringing a pair of pins into contact withtwo different portions of each circuit wiring and then checkingconduction between the positions.

[0004] However, in an area of the circuit board, such as the vicinity ofan integrated circuit, where the circuit wirings are formed in closeproximity to each other, it is difficult to assure a sufficient intervalbetween the pins. On the other hand, a non-contact type inspectionmethod (Japanese Patent Laid-Open Publication No. 09-264919) has beenproposed. However, since this inspection method has still been requiredto bring one pin into contact with each input section of the circuitwirings, it has been suffered from complicated and time-consumingpositioning operations when circuit wirings such as those around anintegrated circuit are in close proximity to each other and each of thecircuit wirings has a short length.

[0005] In view of the problems in the above conventional methods, it istherefore an object of the present invention to provide an apparatus anda method capable of inspecting a circuit board at a high speed.

DISCLOSURE OF THE INVENTION

[0006] In order to achieve the above object, according to a first aspectof the present invention, there is provided an apparatus for inspectinga circuit board incorporating an integrated circuit, comprising: drivemeans for forcibly driving the integrated circuit to generate outputsignals sequentially from a plurality of output terminals of theintegrated circuit; detect means for detecting in a non-contact manner avoltage change in a plurality of circuit wirings connected to the outputterminal; comparison means for comparing the magnitude of the detectedvoltage change to a given value; and defect determination means fordetermining a defect in the circuit wirings according to the comparisonresult in the comparison means.

[0007] In the first aspect of the present invention, the detect meansmay be adapted to generate a waveform representing the voltage change,and when the waveform includes an abnormal waveform, the defectdetermination means may be operable to identify defective one or ones ofthe plurality of circuit wirings according to the location of theabnormal waveform on a time axis.

[0008] The detect means may include a sensor board opposed to theplurality of circuit wirings in a non-contact manner to detect thevoltage change any one part of the plurality of circuit wiring. Further,the sensor board may include a single metal plate which has a dimensionarranged to cover the plurality of circuit wirings and includes a singleoutput terminal.

[0009] The plurality of circuit wirings may be driven to sequentiallygenerate pulse signals as the output signals. In this case, the detectmeans may be operable to sequentially differentiate the pulse signalsand add the differential values to present the sum as a single outputwaveform representing the voltage change.

[0010] The determination means may be operable, responsive to thecomparison result in the comparison means indicating that the magnitudeof the voltage change is equal to or less than the given value, todetermine that the circuit wiring corresponding to the voltage changeincludes a disconnection.

[0011] According to a second aspect of the present invention, there isprovided an apparatus for inspecting a circuit board for use in an LCDdriver, comprising: detect means for detecting in a non-contact manner avoltage change in all of circuit wirings connected in a one-on-onearrangement to terminals of an LSI for use in an LCD driver;determination means for determining whether or not the magnitude of thedetected voltage change is normal or abnormal; and identification meansresponsive to the determination of an abnormality in the voltage changeto identify defective one or ones of the circuit wirings according tothe timing of occurrence of said abnormal voltage change.

[0012] In the second aspect of the present invention, the apparatus mayfurther include drive means for forcibly driving the LSI to generateoutput signals sequentially from the terminals of the LSI.

[0013] The terminals may be segment terminals. In this case, thedetermination means may be operable responsive to the voltage changeless than a given value to determine that the circuit wiringcorresponding to the voltage change includes a disconnection.

[0014] Alternatively, the terminals may be common terminals. In thiscase, the determination means may be operable responsive to the voltagechange greater than a given value to determine that the circuit wiringcorresponding to the voltage change includes a disconnection.

[0015] The determination means may be operable responsive to the voltagechange greater than a given value to determine that the circuit wiringcorresponding to the voltage change includes a short-circuit.

[0016] The timing of occurrence of said abnormal voltage change may bedefined by a location on a time axis between adjacent timings of frameinversion detected as periodical major voltage changes in the detectmeans.

[0017] In order to achieve the above object, according to a third aspectof the present invention, there is provided a method for inspecting acircuit board incorporating an integrated circuit, comprising the stepsof: forcibly driving the integrated circuit to generate output signalssequentially from a plurality of output terminals of the integratedcircuit; detecting in a non-contact manner a voltage change in aplurality of circuit wirings connected to the output terminal; comparingthe magnitude of the detected voltage change to a given value; anddetermining a defect in the circuit wirings according to the comparisonresult in the comparing step.

[0018] In the third aspect of the present invention, the detecting stepmay include the step of generating a waveform representing the voltagechange, and the defect determination step may include the step of whenthe waveform includes an abnormal waveform, identifying defective one orones of the plurality of circuit wirings according to the location ofthe abnormal waveform on a time axis.

[0019] The detection step may include the step of positioning a sensorboard opposedly to the plurality of circuit wirings in a non-contactmanner to detect the voltage change in any one part of the plurality ofcircuit wiring. In this case, the sensor board may include a singlemetal plate having a dimension arranged to cover the plurality ofcircuit wirings, the metal plate including a single output terminal.

[0020] The driving step may include the step of forcibly driving theplurality of circuit wirings to sequentially generate pulse signals asthe output signals, and the detecting step may include the step ofsequentially differentiate the pulse signals and add the adjacentdifferential values to present the sum as a single output waveformrepresenting the voltage change.

[0021] The determining step may include the step of responsive to thecomparison result in the comparing step indicating that the magnitude ofthe voltage change is equal to or less than the given value, determiningthat the circuit wiring corresponding to the voltage change includes adisconnection.

[0022] According to a fourth aspect of the present invention, there isprovided a method for inspecting a circuit board for use in an LCDdriver, comprising the steps of: incorporating in the circuit board anLSI for use in an LCD driver; forcibly driving the LSI to generateoutput signals sequentially from all of circuit wirings connected in aone-on-one arrangement to terminals of the LSI; detecting a voltagechange in the circuit wirings in a non-contact manner; determining ifthe magnitude of the detected voltage change is normal; and responsiveto the determination of an abnormality in the voltage change,identifying defective one or ones of the circuit wirings according tothe timing of occurrence of said abnormal voltage change.

[0023] In the fourth aspect of the present invention, the terminals maybe segment terminals. In this case, the determining step may include thestep of responsive to the voltage change less than a given value,determining that the circuit wiring corresponding to the voltage changeincludes a disconnection.

[0024] Alternatively, the terminals may be common terminals. In thiscase, the determining step may include the step of responsive to thevoltage change greater than a given value, determining that the circuitwiring corresponding to the voltage change includes a disconnection.

[0025] The determining step may include the step of responsive to thevoltage change greater than a given value, determining that the circuitwiring corresponding to the voltage change includes a short-circuit.

[0026] The timing of occurrence of said abnormal voltage change isdefined by a location on a time axis between adjacent timings of frameinversion detected as periodical major voltage changes in the detectingstep.

BRIEF DESCRIPTION OF THE DRAWINGS

[0027]FIG. 1 is a schematic diagram showing the entire construction ofan inspection system according to one embodiment of the presentinvention;

[0028]FIG. 2 illustrates an equivalent circuit of a sensor, LSI andcircuit wirings in the inspection system according to the embodiment ofthe present invention;

[0029]FIG. 3 is a block diagram mainly showing the internal constructionof the inspection apparatus of the inspection system according to theembodiment of the present invention;

[0030]FIG. 4 is an explanatory diagram of a method for inspecting acircuit board on the side of SEG terminals by use of the inspectionapparatus according to the embodiment of the present invention;

[0031]FIG. 5 is an explanatory diagram of a method for inspecting thecircuit board on the side of COM terminals by use of the inspectionapparatus according to the embodiment of the present invention;

[0032]FIG. 6 is a flow chart of the inspection method according to theembodiment of the present invention;

[0033]FIG. 7 illustrates an actual waveform detected by the inspectionsystem according to the embodiment of the present invention; and

[0034]FIG. 8 illustrates an actual waveform detected by the inspectionsystem according to the embodiment of the present invention.

DESCRIPTION OF THE PREFERRED EMBODIMENT

[0035] With reference to the drawings, the present invention will now bedescribed in detail in conjunction with a preferred embodiment intendedsimply to show as an example. Therefore, the present invention is notlimited to any arrangement, numerical values and others of elements orcomponents described in this embodiment unless otherwise specified.

[0036] (Embodiment)

[0037] As one embodiment of the present invention, a system forinspecting a circuit board incorporating an integrated circuit will bedescribed below.

[0038] <Construction of Inspection System>

[0039]FIG. 1 is schematic diagram showing the inspection system in aninspection operation of a circuit board 100.

[0040] A liquid crystal display (LCD) driver module 100 as an object tobe inspection has an onboard LCD driving LSI 110. A plurality of firstcircuit wirings 111 (hereinafter referred to as “SEG circuit-wiringgroup”) printed on the circuit board are connected to a plurality ofsegment (SEG) terminals of the LSI 110, respectively. A plurality ofsecond circuit wirings 112 (hereinafter referred to as “COMcircuit-wiring group”) are connected to a plurality of common (COM)terminals of the LSI 110, respectively. Further, a plurality of thirdcircuit wirings 113 are connected to a plurality of input terminals ofthe LSI 110, respectively.

[0041] The inspection system comprises an inspection apparatus 1composed of a computer, an SEG sensor 2, and a COM sensor 3. Theinspection apparatus 1 is a general-purpose computer incorporating anLCD driving program, a circuit and program for analyzing a detectedsignal from each of the sensors, an interface for allowing communicationbetween the sensors and the LCD driver module, and others.

[0042] The inspection apparatus 1 generates an LSI drive signal andsends it to the input terminals 113 of the LSI 110. Voltage changes ineach of the SEG and COM circuit-wiring groups 111 and 112 caused by theLSI drive signal are detected by the sensors 2, 3, and then the signalsdetected by the sensors 2, 3 are analyzed in the inspection apparatus 1.

[0043] The sensors 2, 3 are positioned opposedly to the SEG and COMcircuit-wiring groups 111, 112, respectively, in a non-contact manner.The sensors 2, 3 detect the voltage changes in the SEG and COMcircuit-wiring groups 111, 112 caused by driving the LSI 110, and sendsthem to the inspection apparatus 1 as detected signals. While thedistance between each of the sensors and the correspondingcircuit-wiring group is desired to be 0.05 mm or less, the voltagechanges can be detected as long as the distance is set in 0.5 mm orless. The sensors may be closely placed on the circuit board withinterposing a dielectric insulating material therebetween.

[0044]FIG. 2 shows an equivalent circuit showing the relationship of oneof the sensors, the LSI and the corresponding circuit-wiring group. Asillustrated, it can be assumed that the sensor is connected with the LSIthrough a plurality of capacitive couplings. Thus, pulse waves from theLSI are converted into differential waves on a side of the sensor, andthen these differential waves are received by the sensor as a detectedsignal.

[0045] With reference to FIG. 3, the internal construction of theinspection apparatus 1 will be described below. FIG. 3 is a blockdiagram showing the hardware of the inspection apparatus 1.

[0046] The reference numeral 210 indicates a power supply for supplyinga power to the entire inspection apparatus 1, the reference numeral 211indicating a CPU for performing various operations and controlling theentire inspection apparatus 1, and the reference numeral 212 indicatinga ROM for storing programs executed in the CPU 211, fixed values or thelike, the reference numeral 213 indicating a RAM as a temporary memory.The RAM includes a program loading area for storing loaded programs, amemory area for digital signals received from the sensors, and others.

[0047] The reference numeral 214 indicates a hard disk (HD) as anexternal memory. The reference numeral 215 indicates a CD-ROM drive as aread device for a detachable storage medium.

[0048] The reference numeral 216 indicates an input/output interface.The inspection apparatus sends and receives signals to/from a keyboard218 as an input device, a mouse 219 and a monitor 220 through theinput/output interface 216.

[0049] A jig 221 sends signals to the LCD driver module as a work, andswitches the SEG sensor and the COM sensor. The computer as theinspection apparatus 1 is expanded to have compatibility for inspectingthe LCD driver module, and an interface card 222 and an A/D conversionboard 223 are incorporated therein. The interface card 222 contains anamplifier 222 a. Thus, the detected signal from each of the sensors isamplified by the amplifier, and then sent to the A/D conversion board223. The interface card 222 further includes a power supply 222 b forjig controls. This is a booster operable to vary its supply voltage whenthe work includes a short circuit.

[0050] Various programs such as an LCD-driver control program, jigcontrol program and detected signal analysis program are stored in theHD 214, and each program is loaded on the program loading area of theRAM 213 and executed. An image data (CAD data) representing each shapeof circuit wirings in design is also stored in the HD 214.

[0051] The LCD and/or jig control programs may be installed by reading aCD-ROM with the CD-ROM drive. Otherwise, these programs may be read fromother medium such as a FD or DVD, or may be downloaded via networks.

[0052] Each of the sensors 2, 3 is made of a conductive materialincluding metals such as aluminum or copper, and semiconductors.Preferably, each of the sensors 2, 3 has a dimension capable of coveringall of the circuit wirings or the circuit-wiring groups.

[0053] While FIG. 3 shows one mode in which the single inspectionapparatus 1 is connected to the single jig to inspect the single work, aplurality of interface cards may be incorporated in a single inspectionapparatus to simultaneously inspect a plurality of works.

[0054] With reference to FIG. 4, a method for detecting defects in theSEG circuit-wiring group will be described below.

[0055] The LSI is forcedly driven so that its 1st to N-th terminalsprovide output pulse signals as shown in FIG. 4(a). Each pointdesignated by the arrows X and Y is the timing for switching frames, andeach of the output waveforms from the terminals is reversed.

[0056] The pulse signals as shown in FIG. 4(a) are detected by thesensor 2, and differentiated and added. The resulting sum forms awaveform as a detected signal having a shape as shown in FIG. 4(b). Asillustrated, at the timings X, Y for switching frames, each voltage inall of the terminals raises or turns down simultaneously to generate arelatively high peak periodically. One frame period of time can bedetermined by detecting these adjacent frame-switching points andcounting the lapsed time between the two points. As shown in FIG. 4(c),by checking the output signal of the sensor around a value n L/N derivedfrom dividing the frame time L by the number of the terminals N andmultiplying the resulting quotient by a positive integer n, where n isequal to or less than the number of the terminals N.

[0057] For example, in FIG. 4, despite of existence of an output pulsesignal from the 3rd terminal as shown in FIG. 4(a), no deferentialwaveform is detected in the sensor output or detected signal as shown inFIG. 4(b). Thus, it can be determined that the circuit wiring connectedto the 3rd terminal includes a disconnection, and thereby no voltagechange is caused at the corresponding position of the sensor. Further,if some circuit wirings include a short circuit therebetween, voltage inthe booster circuit is varied by driving the terminal connected to thiscircuit wiring, and then voltage changes are caused in all of theterminals. This leads to a significant disorder in the sensor outputwaveform. FIG. 4(b) shows that the two circuit wirings connected to theN−1-th and N−2-th terminals are short-circuited mutually.

[0058] With reference to FIG. 5, a method for detecting defects in theCOM circuit-wiring group will be described below.

[0059] Differently from the SEG terminals, the COM terminals are turnedon and off in a sequential order during a regular LCD drive. Thus, theCOM terminals are driven in the ordinary way without any additionalparticular control. However, by the ordinary way, the timing of turn-offin one of the terminals is simultaneous with the timing of turn-on inadjacent one, as shown in FIG. 5(a). Thus, if no defect, at any one ofthe timing, the differential value representing a voltage change in oneof the circuit wirings has the same magnitude as but the reverse sign tothat in adjacent one. That is, in a normal state free from any defect,the sensor output waveform formed by adding respective differentialvalues of all of the terminals will have a flat shape. As shown in FIG.5(b), only if one circuit wiring in the circuit group includes adisconnection, two circuit wirings connected to the terminals on bothsides of the terminal of the circuit wiring including the disconnectionhave turn-on and turn-off waveforms, respectively.

[0060] As in the SEG terminals, a relatively high peak is generated ateach of the frame switching timings X and Y. Further, disconnection andshort circuit in the circuit wiring connected to the n-th COM terminalcan be detected based on the frame time L and the number of theterminals.

[0061] Fir example, in the sensor output as shown in FIG. 5(a), adifferential waveform is detected at the 4th position in the dividedtimes. That is, it can be determined that the circuit wiring connectedto the 4th terminal includes a disconnection, and thereby no voltagechange is caused at the corresponding position of the sensor. Further,the waveform of a short circuit is the same as that in the SEGterminals. That is, if one circuit wiring in the circuit-wiring groupincludes a short circuit, voltage in the booster circuit is varied bydriving the terminal connected to this circuit wiring, and then voltagechanges are caused in all of the terminals. This leads to a significantdisorder in the sensor output waveform. FIG. 5(b) shows that the twocircuit wirings connected to the N−1-th and N−2-th terminals areshort-circuited mutually.

[0062] With reference to the flowchart of FIG. 6, the processing flow inthe inspection operation will be described below.

[0063] In Step S-610, each position of frame inversions on a time axisis first detected. This can be achieved by detecting peaks each appearsapproximately periodically and equal to or greater than a given value.In Step S-602, the period of time between the peaks of the frameinversions is then measured to determine a frame time.

[0064] In Step S-603, L/N is derived from dividing the frame time L bythe number of the terminals N. After initializing the terminal number nin Step S-604, n is incremented in Step S-605, and n L/N is calculatedto specify a range on the time axis in which the voltage of the circuitwiring connected to the n-th terminals is to be detected. By comparingthe sensor output waveform falling within in the range to a normalsensor output waveform or comparing a threshold derived from the normalsensor output waveform to a peak of the actual output, it is detectedwhether voltage change is caused in the n-th circuit wiring. Morespecifically, in the inspection operation of the SEG circuit-wiringgroup, when the peak of the actual output is equal to or less than acertain threshold, it is determined that the circuit wiring includes adisconnection. Further, when the peak of the actual output is equal toor less than another threshold, it is determined that the circuit wiringincludes a short circuit. In the inspection operation of the COMcircuit-wiring group, when the peak of the actual output is equal to orgreater than a certain threshold, it is determined that the circuitwiring includes a disconnection. Further, when the peak of the actualoutput is equal to or greater than another threshold greater than thecertain threshold, it is determined that the circuit wiring include ashort circuit.

[0065] If one of disconnection and short circuit is determined in StepS-606, the process proceeds from Step S-607 to Step S-608, and thecircuit wiring number n and its determined defect are recorded. In StepS-609, n is then compared to N in order to determine if the inspectionoperation for the entire circuit-wiring groups is completed. If n isless than N, the process returns to Step S-605. After n is incremented,the processing in Step S-606 to Step S-608 will be repeated. When n isequal to N, the completion of the inspection operation for the entirecircuit-wiring groups is determined, and the processing is terminated.

[0066] When it is required to remove a defective circuit board even ifonly one defect is included in circuit wirings of the circuit board, inresponse to YES in Step S-607, the defect of the circuit board isnotified to a user, and then the processing of this circuit board may beterminated without completing the inspection operation for the entirecircuit-wiring groups. Otherwise, without the storing process in StepS-608, the defect of the circuit board may be simply notified to a user.

[0067] As above, in the inspection system according to this embodiment,disconnection and/or short circuit in the circuit board having theonboard LCD driving LSI as an integrated circuit are detected in anon-contact manner. Thus, even if highly fine circuit patterns areintroduced in the market, it is unnecessary to prepare mechanisms andspend much time for troublesome positioning operations. Further, the jigis not damaged and desired automatic mechanization can be facilitatedbecause any probe is not used in the inspection system.

[0068] In addition, the inspection system according to this embodimentcan inspect a circuit board having an onboard LSI. In the same state,the LSI itself can also be inspected (an inspection of currentconsumption during operation, an inspection and measurement of voltage,an inspection of frame frequency or the like), and thereby the time forinspecting the entire LSD driver module can be remarkably reduced.

[0069] While the inspection system according to this embodiment detectsvoltage changes in the circuit wirings, the quantity and radiativeconfiguration of an electromagnetic wave emitted from the circuit boardmay be detected. When the electromagnetic wave has a given quantity andconfiguration, it is determined that the circuit wiring has a normalcontinuity. If the electromagnetic wave has a quantity less than a givevalue and a configuration different from a given criterion, it isdetermined that the circuit wiring has a defect.

EXAMPLE

[0070] For the purpose of reference, actual sensor output waveforms areshown in FIGS. 7 and 8. FIGS. 7 and 8 show detect waveforms on the sideof the SEG and COM terminals, respectively.

[0071] These data was measured by driving a work having a number 80 ofCOM terminals and a number 128 of SEG terminals and sampling waveformsusing frame outputs as triggers. In particular, the SEG terminals weresequentially driven in units of 32 terminals to generate output signalswith skipping two terminals so as to determine the outputs of the SEGterminals independently.

[0072] As a result, in case of a total number 250 of the SEG and COMterminals, a single work could be inspected within 1.5 to 3 seconds, andfour works arranged in parallel with each other could be inspectedwithin 3 to 7 seconds.

INDUSTRIAL APPLICABILITY

[0073] The present invention can provide an apparatus and method forinspecting a circuit board at a high speed.

What is claimed is:
 1. An apparatus for inspecting a circuit boardincorporating an integrated circuit, comprising: drive means forforcibly driving said integrated circuit to generate output signalssequentially from a plurality of output terminals of said integratedcircuit; detect means for detecting in a non-contact manner a voltagechange in a plurality of circuit wirings connected to said outputterminals; comparison means for comparing the magnitude of the detectedvoltage change to a given value; and defect determination means fordetermining a defect in said circuit wirings according to the comparisonresult in said comparison means.
 2. An apparatus as defined in claim 1,wherein said detect means is adapted to generate a waveform representingthe voltage change, and wherein when said waveform includes an abnormalwaveform, said defect determination means is operable to identifydefective one or ones of said plurality of circuit wirings according tothe location of said abnormal waveform on a time axis.
 3. An apparatusas defined in claim 1, wherein said detect means includes a sensor boardopposed to said plurality of circuit wirings in a non-contact manner todetect the voltage change in any one part of said plurality of circuitwiring.
 4. An apparatus as defined in claim 3, wherein said sensor boardincludes a single metal plate having a dimension arranged to cover saidplurality of circuit wirings, said metal plate including a single outputterminal.
 5. An apparatus as defined in claim 1, wherein said pluralityof circuit wirings are driven to sequentially generate pulse signals assaid output signals, and wherein said detect means is operable tosequentially differentiate the pulse signals and add the differentialvalues to present the sum as a single output waveform representing thevoltage change.
 6. An apparatus as defined in claim 1, whereinresponsive to the comparison result in said comparison means indicatingthat the magnitude of the voltage change is equal to or less than saidgiven value, said determination means is operable to determine that thecircuit wiring corresponding to said voltage change includes adisconnection.
 7. An apparatus for inspecting a circuit board for use inan LCD driver, comprising: detect means for detecting in a non-contactmanner a voltage change in all of circuit wirings connected in aone-on-one arrangement to terminals of an LSI for use in an LCD driver;determination means for determining whether or not the magnitude of thedetected voltage change is normal or abnormal; and identification meansresponsive to the determination of an abnormality in the voltage changeto identify defective one or ones of said circuit wirings according tothe timing of occurrence of said abnormal voltage change.
 8. Anapparatus as defined in claim 7, which further includes drive means forforcibly driving said LSI to generate output signals sequentially fromsaid terminals of said LSI.
 9. An apparatus as defined in claim 7,wherein said terminals are segment terminals, and wherein saiddetermination means is operable responsive to the voltage change lessthan a given value to determine that the circuit wiring corresponding tosaid voltage change includes a disconnection.
 10. An apparatus asdefined in claim 7, wherein said terminals are common terminals, andwherein said determination means is operable responsive to the voltagechange greater than a given value to determine that the circuit wiringcorresponding to said voltage change includes a disconnection.
 11. Anapparatus as defined in claim 7, wherein said determination means isoperable responsive to the voltage change greater than a given value todetermine that the circuit wiring corresponding to said voltage changeincludes a short-circuit.
 12. An apparatus as defined in claim 7,wherein said timing of the occurrence of said abnormal voltage change isdefined by a location on a time axis between adjacent timings of frameinversion detected as periodical major voltage changes in said detectmeans.
 13. A method for inspecting a circuit board incorporating anintegrated circuit, comprising the steps of: forcibly driving saidintegrated circuit to generate output signals sequentially from aplurality of output terminals of said integrated circuit; detecting in anon-contact manner a voltage change in a plurality of circuit wiringsconnected to said output terminal; comparing the magnitude of thedetected voltage change to a given value; and determining a defect insaid circuit wirings according to the comparison result in saidcomparing step.
 14. A method as defined in claim 13, wherein saiddetecting step includes the step of generating a waveform representingthe voltage change, and wherein said defect determination step includesthe step of when said waveform includes an abnormal waveform,identifying defective one or ones of said plurality of circuit wiringsaccording to the location of said abnormal waveform on a time axis. 15.A method as defined in claim 13, wherein said detection step includesthe step of positioning a sensor board opposedly to said plurality ofcircuit wirings in a non-contact manner to detect the voltage change inany one part of said plurality of circuit wiring.
 16. A method asdefined in claim 15, wherein said sensor board includes a single metalplate having a dimension arranged to cover said plurality of circuitwirings, said metal plate including a single output terminal.
 17. Amethod as defined in claim 13, wherein said driving step includes thestep of forcibly driving said plurality of circuit wirings tosequentially generate pulse signals as said output signals, and whereinsaid detecting step includes the step of sequentially differentiate thepulse signals and add the differential values to present the sum as asingle output waveform representing the voltage change.
 18. A method asdefined in claim 13, wherein said determining step includes the step ofresponsive to the comparison result in said comparing step indicatingthat the magnitude of the voltage change is equal to or less than saidgiven value, determining that the circuit wiring corresponding to saidvoltage change includes a disconnection.
 19. A method for inspecting acircuit board for use in an LCD driver, comprising the steps of:incorporating in said circuit board an LSI for use in an LCD driver;forcibly driving said LSI to generate output signals sequentially fromall of circuit wirings connected in a one-on-one arrangement toterminals of said LSI; detecting a voltage change in said circuitwirings in a non-contact manner; determining whether or not themagnitude of the detected voltage change is normal; and responsive tothe determination of an abnormality in the voltage change, identifyingdefective one or ones of said circuit wirings according to the timing ofsaid determination.
 20. A method as defined in claim 19, wherein saidterminals are segment terminals, and wherein said determining stepincludes the step of responsive to the voltage change less than a givenvalue, determining that the circuit wiring corresponding to said voltagechange includes a disconnection.
 21. A method as defined in claim 19,wherein said terminals are common terminals, wherein said determiningstep includes the step of responsive to the voltage change greater thana given value, determining that the circuit wiring corresponding to saidvoltage change includes a disconnection.
 22. A method as defined inclaim 19, wherein said determining step includes the step of responsiveto the voltage change greater than a given value, determining that thecircuit wiring corresponding to said voltage change includes ashort-circuit.
 23. A method as defined in claim 19, wherein said timingof occurrence of said abnormal voltage change is defined by a locationon a time axis between adjacent timings of frame inversion detected asperiodical major voltage changes in said detecting step.